Late Successional Mixed Conifer Forests

Since the 1850s, both timber harvest and large-scale fires have replaced many of the late successional forests in Oregon with younger forests. Many of the remaining late successional forests occur in a patchwork with the younger forests that are managed with shorter rotations to generate timber products. While a mosaic of forest age classes contributes to landscape-scale diversity, many species associated with late-successional forests require large patches of older or mature forests to survive and may be sensitive to changes in the forest seral stage. Late successional mixed conifer forests are particularly important for wildlife, mosses, and lichens. Depending on the ecoregion, Species of Greatest Conservation Need associated with late successional conifer forests include ringtail, fisher, Pacific marten, red tree vole, Marbled Murrelet, Northern Spotted Owl, Oregon slender salamander, and many others.

The Northwest Forest Plan (NWFP) is a comprehensive natural resource planning effort that includes all or part of the Siuslaw, Rogue River-Siskiyou. Mt. Hood, Willamette, Deschutes, Umpqua, and Fremont Winema National Forests in Oregon. The NWFP identifies conservation priorities for species affected by loss and fragmentation of large patches of late successional forests, assessing over 1,000 species. Late Successional Reserves established under the NWFP are intended to ensure enough high-quality habitat to sustain identified species. However, many of the federal lands that are designated as Late Successional Reserves do not include forests at the late successional stage, while others are relatively small “checkerboards” of forests embedded in a matrix of private industrial timber lands, particularly in the Coast Range and Klamath Mountains.

Late successional mixed conifer forests are generally declining on federal lands in the NWFP area, though at a slower rate than before the plan’s implementation. From 1994 until 2020, there was an increase in the acres of late successional stage forest in the NWFP area. However, in 2020, wildland fires driven by strong east winds in the Mt. Hood, Willamette, Umpqua, and Rogue Siskiyou National Forests destroyed many acres of late successional forest. The overall goal of the NWFP is to achieve desired conditions for these forests over decades, a goal that remains feasible but requires sustained effort to manage disturbances like wildfire in fire-prone areas. Particular attention is needed for the fire-prone portions of the NWFP area, where large wildfires have set back forest conditions from desired outcomes.

The US Forest Service’s Wildfire Crisis Strategy Implementation Plan and Oregon Department of Forestry’s 20 Year Landscape Resiliency Strategy are examples of federal and state efforts to address uncharacteristic wildfire in Oregon’s forests. These plans address historical fire suppression, exclusion of cultural burning practices, and the impacts of recent catastrophic and uncharacteristic wildfires by recommending a variety of active management techniques for forests to increase forest resiliency to wildland fire.

Oregon’s state forests are managed to support a healthy balance of timber production, clean water, recreation, and wildlife habitat. The Oregon Department of Forestry (ODF) oversees the Northwest and Southwest State Forest Management Plans, which guide how Board of Forestry lands are managed. These management plans include conservation strategies for both upland forest and riparian habitats and support a wide range of SGCN – including both terrestrial and aquatic species. ODF is currently developing the Western Oregon State Forest Management Plan and the Western Oregon State Forest Habitat Conservation Plan (HCP), which when approved will replace the Northwest and Southwest Oregon State Forest Management Plans and cover about 64,000 acres of ODF managed lands west of the Cascades.

The Oregon Department of State Lands (DSL) manages’ the Elliot State Research Forest, Oregon’s first state-designated research forest. DSL developed a Habitat Conservation Plan (HCP) for the Elliot to protect late-successional forest habitat, which is critical to SGCN such as Marbled Murrelet and Northern Spotted Owl. The Elliot HCP balances forest research and limited management activities with long-term habitat conservation goals.

The Private Forest Accord (PFA) is a compromise agreement made between representatives from Oregon’s timber industry, the Oregon Small Woodlands Association, and prominent conservation and fishing organizations, to modify portions of Oregon’s forest practice laws and regulations in a way that expands protections for fish and amphibians. The changes to the Oregon Forest Practices Act are aimed at avoiding and minimizing the effects that timber harvests and other forest management activities on private forestlands have on these species and the aquatic habitats they depend on. The PFA included new standards for stream classification and protection or stream buffers, steep slopes, roads, and culverts, as well as a grant program to fund riparian and stream habitat restoration projects. These standards may also help to restore some late successional mixed conifer forests located in riparian areas adjacent to streams.

In the southwest Cascades, white firs in overstocked stands often have a high prevalence  of disease, creating a buildup of fuels and putting large ponderosa pines at risk for severe wildfire. Removing these patches of dead, dying, and diseased trees will help create more early seral openings for the benefit of deer and elk and provide a greater mosaic of habitats across the landscape.